Method for forming hollow sheet metal panels



METHOD FOR FORMING HOLLOW SHEET METAL PANELS Original Filed July 22, 1954 R. F. ADAMS July 24, 1962 2 Sheets-Sheet 1 I74 I8 20 I6 IN VEN TOR.

S m M E A N D R A W T F .A D 6 R July 24, 1962 ADAMS 3,045,613

METHOD FOR FORMING HOLLOW SHEET METAL PANELS Original Filed July 22, 1954 2 Sheets-Sheet 2 ]zz l 83 80 FIG. 5 84 77 s2 76 i x 66 if 74 44 8 67 1;, I 48 ]ZZI s4 56 O o 45 FIG.6 5842 41 66 m 7| 72 I4 53 W HT 59 57 2 16 FIG. 7

79 II/W 7a l8 INVENTOR.

RICHA E ADAMS MM ATTORNEYS United States Patent 3,045,618 METHOD FUR FGRMING HGLLQW SHEET METAL PANELS Richard Franklin Adams, Schenectady, N.Y., assignor to Olin Mathieson Chemical Corporation, East Alton, Ill., a corporation of Virginia Original application July 22, 1954, Scr. No. 445,103, new Patent No. 2,949,875, dated Aug. 23, 1960. Divided and this application Oct. 5, 1959, Ser. No. 844,537

5 Claims. (Cl. 113-51) This invention relates to a pressure fitting or connection and more specifically to a fluid pressure injection method for inflation of hollow articles. This application is a division of co-pending application Serial No. 445,108, filed July 22, 1954, now Patent No. 2,949,875.

In the fabrication of hollow articles from sheeting by a method such as the pressure welding method, it is necessary to communicate fluid pressure to the interior surfaces of the embryonic fluid passageways in order to develop the passageways in accordance with a desired layout as predetermined by the presence of a thin layer of separation material, also referred to as stop weld, between these surfaces. It is frequently desirable that such connection or fitting be adaptable for association with the sheet metal units only during the initial manufacturing operations including inflation and be removable before. further fabrication.

In the prior art methods of forcing hollow metal articles to shape by fluid pressure, various fittings have been employed. According to one scheme, threaded fittings are formed or attached in some manner to the structure to be inflated (US. Patent Nos. 1,709,865, Muflly; 1,712,085, Litle; and 2,493,135, Gruetjen). The obvious disadvantage of these is that the addition of such fittings involves a hole punching or a breech forming process, brazing or welding operation together with a threaded operation, all of which are costly and time consuming operations. Other devices used for the purpose are rather complex and require the formation of a flange on the article (US. 1,925,854, Squires; 2,047,296, Squires; and 2,221,539, Gehret) which is rather impractical with sheet material of relatively thin gage and obviously uneconomical for mass production of sheet metal items for the consumer market. A further illustration of these prior complex devices in US. 2,350,541 (Stolen) which, while suitable for large costly items such as an aeroplane propeller blade, would upon reduction to a scale for the purposes of this invention become an assembly of costly small precision parts not adaptable to the sheet metal operation to which this invention relates and difficult to keep in operating condition. Furthermore, none of the foregoing prior devices is capable of either prying open the edge of the sheet at the linearly exposed stop weld or is capable of being connected and further enlarging the opening by insertion and hence each is suitable for use only with a forged or machined end fitting.

Merely applying a pointed tool to the parting line of stop 'Weld appearing at the edge of a sheet to make a tubular entrance and then forcing into the opening a piece of tubing for applying pressure to the sheet and it afterward to remain as an inlet or outlet for a heat exchange unit or the like is not satisfactory. Such a scheme necessitates that the sheet be extremely thick walled so that pressing the tube in will not tear the sheet and still enable the fitting to withstand pressure of up to 10,000 pounds per square inch or higher. This places a limitation on the thinness of gage with which the aforementioned pressure welding method may be practiced. Another disadvantage is that the presence of permanent fittings of this type interferes with the stacking, handling, packing, and shipping of the inflated pressure welded M sheets which may be otherwise planar and capable of being handled just about like ordinary flat sheet.

Therefore, one object of this invention is to provide a method for expanding such hollow articles without resort to permanent connections or the special metal forming operations at the proposed inlet as is necessary with prior art devices. Still another object is to provide a new and improved method for quickly forming a hermetically sealed connection to the undeveloped interior of a pressure welded sheet metal blank and, if desired, for providing a connection to the developed cavity of such a sheet metal unit for further fabricating operations. Other objects and advantages will be apparent from the description and accompanying drawing relating to various preferred embodiments of the invention.

In accordance with this invention, in general terms, a fluid pressure admitting member is provided and is inserted between the sheet material portions or labia surrounding the inlet lamination exposed at the edge of a sheet unit and the labia are compressed about the fluid pressure admitting member and against each other immediately adjacent said member by a clamping member. The pressure admitting member, formed preferably of stainless steel, consists of an inflation needle or cannula at one end and a high pressure coupling at the other for connection to a source of fluid. Intermediate the needle and the coupling this member is provided with an exterior flange which may be provided with flats or a knurl or the like to permit grasping and in some instances even turning the member which facilitates its removal after the pressure admitting member has served its purpose. The inflation needle is a tubular member which may be either circular, oval, or lenticular in cross section, and the forward end of it is at least rounded to facilitate insertion between the partially separated labia of the edge opening. The forward end of the needle in its preferred form may be provided with either a chisel-shaped point or a conical point to enable its being inserted to bring about initial separation of the labia. The external member takes the form of a clamping device capable of swaging the labia tightly about the needle and for closing up any gap which may occur at the corners of the labia and which would permit a leak between the exterior of the needle and the interior of the labia. The parts of the clamping member may be borne either by the press platens between which the hollow sheet unit is inflated or by an implement or tool also carrying the fluid pressure admitting member.

The general nature and extent of the invention will be better understood from a description of the several specific embodiments illustrated in the accompanying drawing in which:

FIGURE 1 is a side elevational View partially in cross section showing part of a heat exchange unit undergoing inflation in accordance with an embodiment of this invention;

FIGURE 2 is an elevational partial view taken on line II-II of FIGURE 1;

FIGURE 3 is a perspective fragmentary view showing a fitting associated in accordance with this invention with a pressure welded sheet metal unit such as a refrigerator evaporator prior to inflation;

FIGURE 4 is a cross sectional view showing a modification of the needle device of FIGURES 1 and 2;

FIGURE 5 is an elevational partial view of a device in accordance with another embodiment of the invention;

FIGURE 6 is a side cross sectional view taken on line VI-VI of the device of FIGURE 5 into which a sheet metal unit has been inserted in accordance with this in- 'vention;

FIGURE 7 is a cross sectional view taken on line 3 VIIVII of FIGURE 6 the better to illustrate the structural details; and

FIGURE 8 is a perspective view of the front end of the needle shown in FIGURES 5, 6 and 7.

In FIGURES 1 and 2, a pressure welded sheet 1 is shown inflated between press platens 2 and 3 with a fluid pressure communication device in accordance with one embodiment of this invention. The pressure admitting member consists of circular tubular needle 4 with a rounded end 21 and a bore which is in communication with the bore of a coupling 5 such as 2. Hanson fitting or the like, suitable for connection with a source of high pressure fluid. The enlarged midsection between the needle 4 and coupling 5 is preferably provided with an exterior flange 6 which is serviceable not only as a grasping and turning means but also as a positioning means. The exterior clamping member is a two part clamp consisting of an upper jaw 7 supported on upper platen 2 with the aid of fastening means such as bolts 8 and a lower jaw 9 supported on lower platen 3 with the aid of any suitable fastening means such as bolts 10. The lower jaw 9 is preferably provided with an arcuate seat 24 having an arcuate groove 25 for reception of the flange 6. Desired positioning of jaws 7 and 9 is accomplished with the aid of shims 26 and 27, respectively. As shown in FIGURE 2, the upper jaw 7 is provided with spaced pressure pads 11 and 12 intermediate which is the arcuate die surface 13 adapted to compress upper labium 14 of sheet 1 against needle 4 with slight plastic deformation. Similarly lower jaw 9 is provided with pressure pads 15 and 16 intermediate which is disposed arouate die surface 17 adapted to compress lower labium 18 of sheet 1 with slight plastic deformation tightly against needle 4. Pressure pads 11, 12, 15 and 16 of generally rectangulaishape and flat surfaced usually are adapted to compressively and plastically deform or swage the metal of the sheet 1 immediately adjacent the inserted needle 4 at the corners 19 and 20 of the labia 14 and 18 so as to accomplish a form fitting seal about the needle.

In operation, the inlet lamination 22 which presents itself as a line at edge 34 of the flat rolled sheet metal unit 1 is first located, as shown in one part of FIGURE 3, and the labia 14 and 18 are initially pried apart in any manner with any suitable instrumentability after which the rounded end 21 of needle 4 is presented to and inserted into the opening at lamination 22 until the edge of sheet 1 is abutted against the enlarged midsection of the pressure admitting member which acts at a stop 23. The entire unit 1 is next placed between the opened platens 2 and 3 of a press where the pressure admitting member, connected to a fluid presure supply line 31 as shown in FIGURE 3, is positioned properly between the jaws 7 and 9 of the exterior clamping member by seating flange 6 in arcuate groove 25 in the lower jaw 9. The platens 2 and 3 of the press are then brought together to the desired closed spacing at which position jaws 7 and 9 have been articulated to their position of closest approach. In this position arcuate die surfaces 13 and 17 of jaws 7 and 9 respectively compress the labia 14 and 18, which delineate lamination 22 of sheet 1, about the major circumferential portion of the exterior side wall of needle 4. In this position of the jaws, pressure pads 11 and 15 are brought into such close spacing as to deform the sheet 1 sufficiently to reduce the thickness of the metal noticeably at 28 immediately adjacent the needle 4 so as to close up the opening at corner 19 of the labia and to compress the metal at this corner firmly against needle 4. Similarly pressure pads 12 and 16 act on the metal at 29 to accomplish closure and compression at corner 20 of the labia 14 and 18. The deformation, evidenced by a bead 30 of deformed metal along the outer periphery of the compressed areas 28 and 29, provides a hermetic seal. While thus secured between needle 4 and the die surfaces of jaws 7 and 9, the separated labia form a fluid pressure connection enabling inflation between platens -2 and 3 to erect fluid passageways such as 32 and 33 in the sheet metal unit 1.

In the form of inflation needle shown in FIGURE 4 the shape in cross section is lenticular and tapers down mostly laterally to a somewhat smaller cross section at the point which is preferably necked down and rounded but conical pointed, knife blade shaped, or chisel-shaped, i.e. has a point or linear edge, to facilitate entry between and even initial parting of the labia 14 and 18 at lamination 22 at edge 34. Convex upper face 35 of the needle operates on labium 14, for example, while lower face 36 operates on labium 18. Lateral edges 37 and 38 are adapted to the form of lamination 22 when opened at the corners 19 and 20. This form of needle may be advantageously provided with a dual bore consisting of passages 39 and 40 extending up toward the chisel point at the forward end but terminating short of the point in lateral outlets, preferably rearwardly extending and opening at the lateral edges 37 and 38 respectively at points forwardly of where the jaws 7 and 9 press upon the needle. This design of needle and its bend-back fluid passages minimizes the chances of scraping metal into the passages 39 and 46 to cause a closure. While the openings of these passages may be also disposed on surfaces 35 and 36, it is preferred that they be at edges 37 and 38 inasmuch as these are more tapered and are least pressed by the metal of sheet 1 at the lamination 22.

In the embodiment of FIGURES 5, 6 and 7, the pressure admitting member and the external compression member are constructed as parts of a single implement of mechanism, which includes a needle or cannula 41, an external compression applicator 42, a transmitter member or transmission sleeve 43, a compression operator 44 and a carrier and impact block 45 to one end of which the needle 41 is connected and near the other end of which there is attached any suitable high pressure coupling 46.

The carrier block 45, which is a piece of steel of generally cylindrical shape, is provided with a fluid passageway or bore 47 communicating with both the needle 41 and the coupling 46. Mounted on the carrier block 45 is the compression applicator 42 and the transmitter 43 the latter two of which are screw threadedly engaged at external threads 48 on applicator 42 and internal threads 49 on the transmitter 43. Fixed angularly about the carrier block 'by any suitable fastening means such as set screw 50 is a guide and support ring 51 from which there extends handle 52 which may take the form of a pistol grip by which the entire mechanism of this embodiment may be supported or grasped manually and manipulated as desired. The rear end of shank 53 of block 45 is adapted to be struck by a mallet, for example, or by an air hammer yieldably carried on lugs 54 and 55 integral with the carrier block 45 to drive needle 41 between the labia 14 and 18 of sheet metal unit 1 as shown in FIGURE 6. Also mounted on carrier block 45 are thin, forwardly extending pins 56 and 57 which slidably engage with holes 58 and 59 in the applicator and prevent rotational movement of the applicator 42 as sleeve 43 and its threads 48 are turned. The carrier annular protrusion 60 forms an abutment for the internal flange 61 of the sleeve 43 and takes the reaction force as the sleeve is turned down on applicator 42.

Needle 41 consists of circular shank 62 at the posterior with a suitable easily engageable and disengageable mechanical coupling such as spline 63 at one end and with a flange 64 near the other serving as a stop for the edge of the sheet metal unit 1, as shown in FIGURE 6. Ahead of the shank 62, the needle 41 has a tapering conical portion 65 designed for coaction with jaws 66 and 67 of compression applicator 42. At the front end, the needle terminates in a conoidal pointed shape 68 with a chisel edge 69 at which there is an opening 70 set 'back from and 'bisecting the edge 6?. Opening 70 is in communication with the bore 71 of the needle. Between the point shape 68 and the conical portion 65 is a circular tubular extension 72 of the needle the purpose of which is to position the point 68 and its opening sufficiently ahead of the jaws 66 and 67 so as to make the point readily visible and easy to apply to the edge of sheet unit 1 to spread apart the labia 14 and 18 while the jaws 66 and 67 are in the forward open position and so as to place the opening 76 ahead of the jaws 66 and 67 dur ing the compression operation which would otherwise seal the opening.

Mounted slidably on the forward cylindrical portion 73 and pins 56 and 57 of the carrier block is the compression applicator 42 which takes the form of a cup'like or hollow cylinder the front of which at jaws 66 and 67 is solid except for the slot 74 intermediate the jaws and which terminates at 75 short of the open rear end of the cylindrical body of the applicator 42 which is thus nearly bisected by the slot. The applicator is provided with external threads 48 engageable with the internal threads 49 of the sleeve 43. Where desired, threads 48 and 49 may be tapered pitch threads to accentuate the clamping action obtainable. The hollow cylindrical body of the applicator 42 is so formed as to be somewhat sprung open at the front end of the slot 74 so that compression applicator jaws 66 and 67 are spaced apart yieldably a greater distance when the threads 48 and 49 are in but minor or no engagement. As the threads are screwed into greater engagement the distance between the jaws 66 and 67 at slot 74 is reduced. Upper jaw 66 is provided at the slot 74 with pressure pads 76 and 77 and the lower jaw 67 is provided at the slot 74 with pressure pads '78 and 79. .Between pads 76 and 77, the upper jaw 66 is provided with an arcuate die surface 80 which is part of a cone larger than the conical portion 65 of the needle 41 by an amount slightly less than the thickness of the lahium 14. Between pads 78 and 79, the lower jaw 67 is provided with an arcuate die surface 81 which is part of the same cone as the die surface 80 of the upper jaw 66.

Sleeve 43 is rotatably mounted on carrier block 45 and engages at its internal threads 49 with the threads 48 of the applicator 42 so as to impart longitudinal movement to the applicator as sleeve 43 is turned by the compression operator 44 'which takes the form of a rotatable ring from which there extends a handle 82. The compression operator ring 44 is mounted rotatably on the sleeve 43 and engages by means of the flip-flop pawl 83 with it at the ratchet teeth 84 carried externally about the sleeve 43. Operator ring 44 is rotatably confined on sleeve 43 by support ring 51 which together with pro trusion 60 constrains sleeve 43 at flange 61 longitudinally while permitting rotational movement on both sleeve 43 and operator ring 44.

The form of the needle point 68, more clearly illustrated in FIGURE 8, is advantageous in that the opening 70 is set back from the bisected edge 69 and hence will not tend to pick up particles of metal or to become shut as edge 69 pries open the labia 14 and 18 of sheet 1.

In operation, the device of this embodiment while grasped or supported at grip 52 is manipulated so as to present edge 69 of the separable needle 41 to the edge of sheet unit 1 in proper position for prying open the labia 14 and 18. When so positioned, hammer blows are struck upon shank 53 of the carrier block 45 either manually or by means of an air hammer attached at lugs 54 and '55 to drive needle 41 between the labia until the edge portion of sheet unit '1 has passed into slot 74 between jaws 66 and 67 sufiic-iently to seat the labia 14 and 18 against flange 64 on the needle 41. Next, with the pawl 83 properly set for screw-down operation, the handle 82 is oscillated manually or otherwise to put pawl 83 carried on compression operator ring 44 into one-way positive engagement with the ratchet teeth 84 on transmission sleeve 43, thereby turning the sleeve 43 to screwdown the compression applicator 42. This operation,

which brings the jaws 66 and 67 closer together and also toward the conical portion of the needle 41, results in seizure and swagi-ng of labia 14 and 18 between the needle 41 and the jaws 66 and 67 which is shown in FIGURE 7.

When the jaws are positioned as shown in FIGURE 7, at which position pressure pads 76 and 77 and arcuate die 86 of jaw 66 deform the metal of sheet unit 1 between them and .pressure pads 78 and 79 and arcuate die 81 of jaw 67, fluid pressure is released to enter at coupling 46 and to be admitted into the interior of sheet metal unit 1 via the bores 47 and 71 of the block 45 and needle 41, respectively.

Upon completion of the inflation operation, after the fluid pressure is shut ofi, the jaws 66 and 67 are opened by throwing the flip-flop pawl 83 to engage with teeth 84 to accomplish unscrewing the applicator body 42 and sleeve 43 as handle 82 is again oscillated. Release of the coupling 63 permits the needle 41 to remain in sheet unit 1, if desired. Otherwise coupling 63 may be dispensed with and the entire device together with needle 41 is removable from the inflated sheet metal unit 1.

While the compression operator has been described as including the mechanical elements of a pawl, a ratchet and a screw threaded transmission sleeve it is to be understood that this preferred embodiment is only illustrative of the inventive principle involved and that the compression clamp operating means may be a pneumatic or hydraulic cylinder actuated possibly by the inflation medium. it is evident to those skilled in the art that this embodiment is amenable to inclusion of a fluid pressure valve operated by a trigger located in the piston grip 52 which would initiate not only a fluid pressure actuated clamping pressure applicator but also feed fluid pressure for inflation to the needle 41.

By means of this invention there is obtained not only a hermetic seal during the step of fluid pressure inflation of a sheet metal unit having an internal pattern of lamina but also the provision of a connection that may be retained with the sheet after inflation to aid in other manufacturing operations such as the washing and the drying of the interior walls of the passageways, after which the connection is readily removable.

It will also be evident to those skilled in the art that this invention has utility in connection with inflation of articles made from sheet material by methods other than pressure welding wherein an interposed stop weld material is employed.

Since many other embodiments of this invention may occur to those skilled in the art, it is to be understood the foregoing is intended by way of illustration of a preferred embodiment and not as a limitation of the scope of the present invention except as set forth in the appended claims.

What I claim is:

1. In the method of forming passages by fluid pressure inflation in a single sheet of partially laminated metal having within its interior unwelded double walled port-ions at the lamina separated by a thin layer of stop weld material defining embryonic passageways in the sheet including an inlet lamination extending toward an edge of said sheet and connecting with said double walled portions, the steps comprising locating the inlet lamination at an edge of said sheet between opposed sheet metal labia and forming an opening thereat by driving a cannula into said opening to separate and hold apart said labia preparatory to admission of fluid under pressure into said sheet, adjustably clamping the said labia about the said cannula with sufficient pressure adjacent the corners at the said labia to compressively deform the metal at least at said corners and forge it substantially completely around the said cannula whereby said cannula is frictionally retained in and hermetically sealed with respect to said labia, and injecting through said cannula a fluid under sufiicient pressure to distend said double walled portions.

2. A method of forming passages in a partially laminated and distendable sheet blank structure having within the confines of its interior unwelded double walled portions at the lamina defining embryonic passageways in the undistended structure and having an inlet lamination extending to an edge of said structure and defined by opposed sheet metal labia disposed in contiguity to form a linear part connecting with an unwelded portion of said structure which comprises the improvement of inserting a cannula into said part in fixed positioned relationship to separate and hold apart said labia, thereafter clamping the said labia about the said cannula in form fitting relationship while simultaneously swaging most severely immediately adjacent the corners of the said labia so as to compressively deform the said structure at least adjacent said corners whereby a hermetically sealed connection including said cannula is finally provided for detachable coupling to a fluid source and for admission of said fluid under inflating pressure into the structure between said double walled portions to effect distention, and injecting through said cannula a fluid under sutficient pressure to distend said double walled portions.

3. A method of forming passages in a partially laminated blank sheet structure having within the confines of its interior separated double walled portions at the lamina defining embryonic passages in the distended structure including an inlet lamination extending to an edge of sai structure and connecting with said double walled portions comprising the steps of inserting a cannula into said inlet lamination at said edge for admission of fluid pressure into said double walled portions, clamping the labia of said inlet lamination at said edge about said cannula in form fitting relationship while simultaneously swaging the portions of said structure immediately adjacent the corners of said labia so as to compressively deform said structure at least in said portions of said structure whereby said cannula is hermetically sealed within said inlet lamination, and injecting through said cannula a fluid under sufficient pressure to distend said double walled portions.

4. A method of forming passages by fluid pressure infiation in a single sheet of partially laminated metal having within the confines of its interior separated double walled portions at the lamina defining embryonic passageways in the sheet with said double walled portions having an inlet lamination extending to an edge of said sheet whereat said inlet lamination is defined by opposed sheet metal labia comprising the steps of forming an opening connecting with said double walled portions of said sheet by separating said labia of said inlet lamination at said edge of said sheet, inserting a cannula into said opening for admitting fluid under pressure into the lamina between said double walled portions, swaging said labia about said cannula by clamping said labia about said cannula together with portions of said sheet immediately adjacent the corner of said labia with suflicient pressure to compressively deform the metal of said labia about said cannula and said portions of said sheet whereby said cannula is hermetically sealed within said inlet lamination, and injecting through said cannula a fluid under suflicicnt pressure to distend said double walled portions.

5. A method for forming passages in a distendable blank having a portion of its interior within the confines of the periphery of said blank adapted for inflation with fluid pressure into a system of fluid passages for containment of a fluid and having a portion thereof extending to an edge of said blank forming an opening into said interior comprising the steps of inserting a cannula into said opening between the labia thereof for admission of a fluid pressure into said interior, clamping the said labia of said opening about said cannula in form fitting relationship while simultaneously swaging the portions of said structure immediately adjacent the corners of said labia so as to compressively deform said structure at least in said portions of said structure whereby said cannula is hermetically sealed within said opening, and injecting through said cannula a fluid to distend said portion of its interior into fluid passages.

References Cited in the file of this patent UNITED STATES PATENTS 1,764,561 Gulick June 17, 1930 2,716,275 Matthysse Aug. 30, 1955 2,882,588 Rieppel Apr. 21, 1959 FOREIGN PATENTS 695,640 Great Britain Aug. 12, 1953 air 

